Sealing device

ABSTRACT

Apparatus for creating a seal between an axle journal and a bearing housing is disclosed, particularly for use in apparatus for dewatering or washing material suspensions. The apparatus includes a stator ring, a pair of diagonally disposed guide pins supporting the stator ring with respect to the bearing housing so that the stator ring can be angled in a plane with respect to the pair of guide pins, a sealing ring for creating a seal between the stator ring and the axle journal, a bellows for creating a seal between the bearing housing and the stator ring, and at least one resilient member for urging the stator ring in abutment against the sealing ring.

This invention relates to a sealing device for sealing between bearinghousing and axle journal of a roll, the two bearing housings of whichfor the axle journal bearings are movable in the direction across theaxle.

The invention also relates to a device for dewatering and/or washingmaterial suspensions (for example pulp suspensions), comprising at leastone cylindric rotary roll, which is surrounded by a casing with inletfor the material suspension, and which against an element forms anoutlet gap for the egress of the material suspension, where the axlejournals of the roll are mounted in bearings supported by bearinghousings, which are movable for taking up variations in the width of theoutlet gap, and sealing devices are provided for sealing between thebearing housing and axle journals.

SE 504011-C2, SE 515543-C2 and SE 501719-C2 show examples of dewateringdevices, which comprise liquid permeable press rolls forming betweenthemselves a nip for dewatering a material suspension of wood fibrepulp. The pulp suspension is supplied to a portion of the device, whichis under pressure and surrounded by a casing, and the dewatered pulpegresses through the nip. The pulp suspension usually is supplied eitherfrom above or from below, as appears from these references. The width ofthe outlet gap can vary, depending on the properties of thesuspension-which can be different along the length of the roll, and thusthe roll can be angled in relation to the bearing housing. It may alsobe necessary to adjust the nip, i.e. to move at least one roll towardsor away from the other roll, and during the movement the roll can beslightly angled. The pulp suspension is aggressive, and if it leaks intothe bearings, the bearings will be destroyed. The sealing against thebearings, therefore, is of vital importance and an essential risk factorfor the accessibility of the device.

Present dewatering devices use as sealing between the bearing housingand axle stuffing boxes and V-ring sealings (of rubber). They do notwithstand, however, the aggressive environment of the pulp suspensionand are destroyed and lose their sealing capacity.

It is an object of the invention to provide a sealing device for sealingbetween bearing housing and axle journal of a roll, the two bearinghousings of which for the axle journal bearings are movable in thedirection across the axle, where this sealing device shall have a longservice life even in an aggressive environment and allows the axle to beslightly angled in a plane during the movement, and where the sealingalso can take up a certain axial movement. A more specific object is byimproved sealing devices to increase the operational reliability of adevice for dewatering and/or washing material suspensions, comprising atleast one cylindric rotary roll, which is surrounded by a casing withinlet for the material suspension, and which against an element forms agap for the egress of pulp, and the axle journals of the roll aremounted in bearings supported by bearing housings movable in thedirection across the axle.

An embodiment of the invention will be described in the following withreference to the accompanying Figures.

FIG. 1 is a cross-section of an illustration in principle of adewatering device for the pulp industry.

FIG. 2 is a view from above of two rolls with intermediate gap comprisedin the device according to FIG. 1.

FIG. 3 is an enlarged section of the rolls seen as indicated by the line3-3 in FIG. 2.

FIG. 4 is an enlarged longitudinal section through one axle journalbearing of one roll.

FIGS. 5 and 6 are detail enlargements of the encircled parts 5 and 6 inFIG. 3.

FIG. 7 is an illustration in principle of the stator ring.

FIG. 1 shows a roller press intended for liquid treatment, for examplewashing and dewatering material suspensions, and there, for example,fibre pulp suspensions, The roller press is described only roughly,because it is already known. Two cylindric, rotary, liquid permeablerolls 9,10 are partially located in a trough 11, which is formed so,that a converging space 12 is formed between the trough 11 and each ofthe rolls 9,10. Each space 12 has an inlet 13 for the materialsuspension. Each space 12 can also have inlets for treatment liquid.Between the rolls 9,10 a gap 14 is formed, a so-called press nip,through which the dewatered pulp passes. At the inlet 13 a longitudinalsealing 19 is provided to seal between the trough 11 and thecircumference of the rolls 9,10, so that the trough 11 forms a tightcasing about the lower portions of the rolls.

FIG. 2 shows in a schematical way the two rolls 9,10 with axle journals21, 22, 23, 24 seen from above. The Figure also shows the end walls25,26 of the trough 11. In the end walls a bearing housing 30, 57, 31,58 is provided for each of the axle journals 21, 22, 23, 24. The axlejournals 21, 22, 23, 24 are mounted in bearings in the bearing housings30, 57 and 31, 58, and sealing devices 27,27′ and respectively, 28,28′seal between the axle journals and bearing housings. The bearinghousings for the axle journals are movable horizontally, so that the gap14 between the rolls 9,10 can be changed as will be described withreference to FIG. 3. The moving of the bearing housings, and thereby ofthe axle journals of the bearing housings, can take place individually,and during the moving, therefore, the roll can be angled in relation tothe bearing housing, as shown in FIG. 2, and the width of the gap 14will then temporarily not be equal along the entire roll length, asshown in FIG. 2. This subjects the sealing devices 27,27′, 28,28′ tolarge requirements.

FIG. 3 shows the end wall 25 and two bearing housings 30, 31, which arehorizontally slidable along guide surfaces 32, 33 in the end wall 25, asshown in FIG. 4. When the suspension passes the gap 14, a line load isobtained on the rolls. The line load can vary along the length of thegap and over the time. This is due to the fact that the properties ofthe suspension vary, such as for example the fibre network. Greatforeign matter can also enter the process and pass through the gap 14.Hydraulic cylinders 34, 35 and, respectively, 36, 37 are provided toprevent a pre-determined level of the line load to be exceeded. If thisshould happen, the dewatering arrangement can be damaged. The strokelength of the hydraulic cylinders can be, for example, 20 mm. Thehydraulic cylinders for one roll, for example the hydraulic cylinders34, 35 for the roll 9, can be replaced by stationary stops, if it isdesired to guide the gap width (line load) by only one roll.

FIG. 4 shows the bearing housing 31 with one bearing 38 for the axlejournal 23 and the sealing device 27, which seals between bearinghousing and axle journal. The bearing at the embodiment shown is ofspheric type and, thus, can take up angle changes.

FIGS. 5 and 6 show on an enlarged scale the parts 5 and, respectively, 6in FIG. 4 with the sealing device 27. The sealing device 27 comprises astator ring 40, which is supported a.o. by two guide pins 41, a sealingring unit 47, a bellow means 56 and at least one resilient element 48(at the embodiment shown the resilient element is a spring).

The sealing ring unit 47 is intended to be tight-sealing against theaxle journal 23 and to rotate with the axle journal 23, and to sealagainst the stator ring 40. The sealing ring unit 47 at the embodimentshown comprises a holding ring 42, which is tight-sealing against theaxle journal 23 with an O-ring 43 and rotates with the roll by carryinglocking pins 44. The sealing ring unit 47 at the embodiment showncomprises also a sealing ring 55 of solid glide material, for examplegraphite, which is supported by the holding ring 42.

FIG. 7 shows an illustration in principle of the stator ring 40 with twofirst recesses 60 for the guide pins 41 and eight second recesses 61 forthe spring 48. The device shown thus comprises eight springs 48, but itmay, of course, comprise a greater or smaller number of springs 48. Thesprings 48 are located in the bearing housing 31 and act against thestator ring 40. The springs 48 are intended to take up relativemovements between the bearing housing 31 and stator ring 40 and toensure that the stator ring abuts the sealing unit 47. The sealing,thus, can take up axial movement and can rise due to wear between rotaryand stationary parts and when different parts of the device are heatedunequally rapidly, so that the parts will have a different heatexpansion.

The guide pins 41 are arranged diagonally and vertically in relation toeach other in the stator ring, and each guide pin 41 has at its frontend a top 45. Each guide pin 41 is slidable in its recess 60 in thestator ring 40. The top 45 and recess 60 are formed in such a way inrelation to each other that the stator ring 40 can be angled slightly inthe horizontal plane. The top 45 suitably is spheric.

The bellow means 56 is intended to take up relative movements betweenthe bearing housing 31 and stator ring 40. The bellow means 56 istightly attached to the stator ring 40 and to the bearing housing 31, inorder to seal there between and comprises a bellows 50. The bellow means56 at the embodiment shown comprises for the attachment of the bellows50 to the bearing housing a bipartite outer ring 49 with a first ringportion 63, which is tightly attached to the bearing housing 31, and asecond ring portion 64, and the bellows 50, which is ring-shaped, isclamped between the first and second ring portion 63 and 64 by externalfastening means 65, for example screws. The bellow means 56 furthercomprises an inner ring 66, which by inner fastening means 67 tightlyclamps the bellows 50 against the stator ring 40. As the bellows isrigidly clamped at its outer edges (relative to the stator ring and,respectively, bearing housing), it need not be of resilient material(for example rubber), but can be of a more durable material, for examplePTFE, which is not destroyed by the aggressive environment, as forexample a pulp suspension. A conventional additional radial sealing 52is provided at the embodiment shown near the bearing at the axlejournal, in order to separate the oil in the bearing from the air-filledclosed space 53. The suspension in the trough is indicated in FIG. 5 bythe reference 54.

The dewatering means shown is only one example, and the dewateringmeans, thus, can be of a type other than the one shown. The materialflow through the gap 14, for example, can be downward instead of upward.The sealing device, of course, can be provided for use in means otherthan dewatering means.

At the embodiment shown the sealing device is arranged so that the axlecan be angled slightly in the horizontal plane. The sealing device, ofcourse, can also be arranged so that it allows angling in other planes,depending entirely on the type of means, in which the device shall beused.

The invention, of course, is not restricted to the embodiment shown, butcan be varied within the scope of the claims with reference to thedescription.

1-7. (canceled)
 8. Apparatus for creating a seal between an axle journaland a bearing housing for said axle journal, said axle journal beingangularly displaceable in a plane relative to said bearing housing, saidapparatus comprising a stator ring, a pair of diagonally disposed guidepins supporting said stator ring with respect to said bearing housingwhereby said stator ring can be angled in a plane with respect to saidpair of guide pins, a sealing ring for creating a seal between saidstator ring and said axle journal, a bellows for creating a seal betweensaid bearing housing and said stator ring, and at least one resilientmember for urging said stator ring in abutment against said sealingring.
 9. The apparatus of claim 8 wherein said bellows is rigidlymounted with respect to said stator ring and with respect to saidbearing housing, said bellows comprising a non-resilient material. 10.The apparatus of claim 8 wherein said at least one resilient member isdisposed to act between said bearing housing and said stator ring. 11.The apparatus of claim 8 wherein said sealing ring is mounted forrotation with said axle journal.
 12. Apparatus for dewatering or washingmaterial suspensions comprising at least one cylindrical rotary rollincluding a pair of axle journals, said at least one cylindrical rotaryroll separated by a predetermined gap from a second element, a troughsurrounding said at least one cylindrical rotary roll, said troughincluding an inlet for said material suspension, an outlet for saidmaterial suspension comprising said predetermined gap, a pair of bearinghousings, a pair of bearings supported by said pair of bearing housings,said pair of axle journals being mounted in said pair of bearings, saidpair of bearing housings being individually movable whereby said atleast one cylindrical rotary roll can be angularly displaced withrespect to said pair of bearing housings, each of said pair of bearinghousings including a sealing means for creating a seal between said pairof bearing housings and said pair of axle journals, said sealing meanscomprising a stator ring, a pair of diagonally disposed guide pinssupporting said stator ring with respect to said bearing housing,whereby said stator ring can be angled in a plane with respect to saidpair of guide pins, a sealing ring for creating a seal between saidstator ring and said axle journal, a bellows for creating a seal betweensaid bearing housing and said stator ring, and at least one resilientmember for urging said stator ring in abutment against said sealingring.
 13. The apparatus of claim 12 wherein at least one of said atleast one cylindrical rotary roll and said second element is liquidpermeable.
 14. The apparatus of claim 13 wherein said second elementcomprises a second cylindrical rotary roll.